Twitchy II: Dancing Wireman

Introduction: Twitchy II: Dancing Wireman

He, like his predecessor, is a "a self-motivating randomly-switching boingy apparatus, whose own random motion contributes to more random motion."

Don't waste your e-waste! Make something out of it!

Depending on how many hard drives you've eviscerated in your day, you may or may not have discovered that some hard drive motors are removable, others are not:
On these drives, the bottom half of the motor is the same chunk of metal that is also the bottom half of the hard drive itself. I'm sure there are numerous advantages to this idea like increased stability and decreased thickness, but those advantages only benefit the hard drive functionality, interfering with those of us busting open a laptop hard drive intending to harvest a tiny motor for a tiny Twitchy.

But as it turns out, there's more than one way to twitch!

Step 1: Materials

Your materials and tools for this project are identical to those in the original Twitchy, ...with just a few exceptions/additions:

Materials:-Busted, "unremovable" hard drive motor, or, a removable one that you don't remove. I used a dead 6-gig Hitachi DK23AA-60, whose motor is fused to the hard drive case.-~24" or so of small wire. Cat-5 network cable gives you eight lovely color choices.-~24" insulated, stiff copper wire (thick enough to hold a shape during severe twitchiness)-Magnet wire: super-ultra-skinny insulated wire. Buy it in a spool, or harvest it from a transformer.-Wire clothes hangar-5V power supply (lots of different ratings will work, just pick one that doesn't heat up and melt your masterpiece). Currently mine is 800 ma, and runs a bit toastier than I'd like...-Small "zip" ties-Guitar string ferrules, or nuts, or beads, or whatever you prefer to call those little brass things at the end of guitar strings. If you don't have a big pile of these, steal them from a guitar-playing friend, or don't; their only purpose is ballast so you can use a blob of solder or a fishing weight.-Ring Terminals: some you can stick on with pliers, some require solder, but they're all good.

Step 2: Strip the Hard Drive, Test, Solder

Get freaky with your torx wrenches until your hard drive is reduced to a rectangle of aluminum with a motor on it.

On the bottom of the drive, you'll see three or four connection points where the crucial, life-giving wires connect. There is usually a ribbon cable that connects the motor to other bits, but all we need to do is pick three points to solder wires onto: either the connections on the ribbon cable or the motor itself.

At this stage you can do some poking around to see what wires do what: -use your "wall wart" DC converter and a couple of wire leads. Be careful: the amperage and voltage are both pretty low, but electricity is electricity, folks!-connect one wire from the motor to one terminal of the wall wart -connect another wire to the other DC terminal, and poke at the free connections to try to get your motor to wiggle. You'll find that it does. -basically what we're looking for is three spots to which we will stick wires.

When you've decided what to solder to, do it: solder about 8 inches of thin wire (single copper wire from a Cat-5 cable) to each terminal. You may need to scratch away some insulation from the connection points to get enough room for solder. The trick is to get three solid wires connected to dinky little connections that would rather not be soldered to; the nice thing is that there are usually more than one spots to try. Take care not to allow solder blobs from hitting each other and shorting out!

Cut off the end of your DC adapter, strip the wires and solder them to two of your hard drive wires; whichever made the motor twitch!

I squandered a great deal of glue on this project, and this particular blob was probably the most crucial: once all three connections are made, glue them down for security.

Hard drives have lots of seemingly random holes on them: run your wires through, wherever you can find a good spot.

Step 3: Make Your Wire Man

Draw a stick figure in mid-air with copper wire. He (or she) can be in any number of positions, as long as his appendages are somewhat akimbo...

Remember: "human" is only one option: any critter or robot or random abstract mid-air scribble will do the trick!

Make all of the parts and lay them together, bend and tweak, until your pile of your wire becomes a person. I made mine like this: One longer piece formed the head, body, load-bearing leg and it's foot. Another piece became both arms and their hands, and a third piece became his other leg and it's foot. Fewer bits is better for strength.

Scale: he's got circular feet and hands, and he's standing on hard drive. So the diameter of the weight-bearing foot has to fit nicely on the top of the hard drive motor.

Solder: At each point where wire crosses wire, cut through the insulation and slide it back to reveal enough copper for a good connection. Bend the wire around the piece you'll be sticking it to, and give the joint a squeeze with pliers. Now you have a nice, tight joint that would probably stay together even without solder, but solder it anyway because it looks cool. Shoot for a nice glob-o-silver.

Stick him to the motor:Put one or more of the tiny bolts back into the motor and solder his ankle onto it, then glue-gun the foot in place. On a full-sized hard drive you may be able to physically bolt the foot into place (Twitchy One had a paperclip bolted to it's... uh... head), but hot glue works regardless. Careful not to let the glue render your motor un-twitch-able.

Fiddle with his arms and leg until they stick out about the same distance from the center of the hard drive motor so that they are all tracing the outline of the same imaginary circle when you spin them.

Step 4: Make Your Hanger Out of a Hanger

Look at your wire man (or duck, or cockroach, or squid, or squiggle or whatever) from above, adjust him so that he's centered on the hard drive motor, and figure out the diameter of a circle that could be touched by each of his noodelly appendages. Make a mental note of that circle, then write it on a mental post-it note (but add mental tape to it because mental post-it notes fall off as easily as the regular kind).

Now (using your mental note as reference), bend a nice, smooth circle out of your hanger that is the exact size of the outer diameter of your Wire Man's limbs.

Bend the long part of the hanger around itself and squeeze with pliers, so you have a circle with a long straight line sticking out of it. The hanger should hold just fine with a good bend, but you can solder or electrical tape or weld if you're paranoid.

Now bend the straight piece sticking out of the circle into a graceful arc, and then into whatever shape you want that will readily stick to the hard drive body: I went with a spiral, but a rectangle makes good sense!

Step 5: Switch It Up

Solder four of those ring terminal thingies to both ends of two lengths of copper wire, about six inches each.

Bend them around the motor so that they radiate like bicycle spokes from the hub that is the motor. Bend them around the motor so that they orbit planet-like around the sun that is the motor. Bend them around the motor so that they [insert another stupid metaphor here] .

Bend and tweak so that the four ring terminals are equally spaced, and lined up so that they sit directly under the "halo" of the hanger.

Cut the insulation from somewhere on each "switch" wire and pull back to reveal some copper you can use to attach your hard drive's wires. Glue the wires down so that they stay put.

Confused? See the diagram (image #2 on this step). Still confused? Me too.

Step 6: Pendulum Production

Straighten a 3" piece of thick copper wire.

Strip 1" of insulation from one end.

Strip 1/2" of insulation from the other end, and bend into a loop.

Melt/burn/cut away the insulation from an 8" length of thin magnet wire.Solder it to the bent end of the thick copper wire.

Solder three guitar string "ferrules" to the other end of the copper wire. They grab the solder quite well when heated a bit! If you don't have a source for these, use something else: a big solder blob will serve, all you need is a little weight.

Make four of these.

Step 7: Wire It Up

You should have three wires sticking up through your hard drive body from step 2. If you don't, what the heck were you doing back at step 2 besides following the instructions?! Go back to step 2, then come back.

I'll wait.

Welcome back!

Now, solder the #1 "from-the-bottom" wire to a foot or so of small wire (I went with light blue because it matched the hanger I used). Wrap the small wire up the hanger and completely around the circle. Tie it or tape it so it stays put.

Solder the #2 from-the-bottom wire to one of your "switch" wires from step 5.

Solder the #3 from-the-bottom wire to the other "switch" wire from step 5.

At four equally-spaced points on your hanger, right above the ring terminals from step 5, make a cut through the thin wire's insulation and expose some copper.

Solder one pendulum (from step 6) to each copper point, and secure with a drop of hot glue. Be careful not to let the bare wire touch the hanger.

Solder both "switch" wires to one of the power wires. The other power wire goes to the pendulums.

Each pendulum should drop through a ring terminal, without touching.

Step 8: Tweak, Test, Enjoy!

You should now have a Twitchy II, the only thing left to do is tweak a bit.

What you want is for Twitchy to spin around and lightly tap the pendulums, which bump into the ring terminals and make a connection, which jerks the motor to life in one direction or another.

At rest, no pendulum should touch it's terminal ring.

This will require a bit of bending on all bendable bits: Ideally your pendulum should dangle in the exact middle of the ring terminals, and your Wire Man should barely touch each pendulum as it spins.

A 45-degree twist to the ring terminals can help crank up the sensitivity. Careful with the skinny magnet wire: if your Twitchy gets too riled up and bent wrong he can hook a wire and get tangled and angry. Watch out for overheating: if the DC converter becomes too hot to touch, you may have a short, or you may need to do a bit more bending.

Congratulations! You've saved some hardware from the landfill, and created a relic of no redeeming value whatsoever!

Once your Twitchy is dancing along without interruption, activate the disco ball and join in!

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6 Comments

I'm having my high school physics students build these - I thought it would be pretty straight forward but it's turning out to be quite difficult for some. I love seeing them become frustrated and having to step back and rethink the overall concept of which direction the electricity is actually flowing.
Thank you for taking the time to post all your HD motor projects. Can you offer any suggestions to my students? Some of the motors have 4 contacts and others have 3. It seems diagnosing the motor and determining which contact does what is the key to creating the individual circuits.

-Both Twitchy and Twitchy II are still in operation at my desk at work. I've found that the copper contacts tend to suffer from gray gook building up that seems to quite effectively block the current; a quick filing/sanding brings it all back to life.

-I changed to a lower amperage/higher voltage power supply that really increased the boogie!

-The nice thing about this project is that the pressure is off: it doesn't need to do anything but twitch randomly, so you can decide how to wire up a 3- or 4-wire motor just by connecting one of the motor terminals to DC + and poking at the other terminals with DC - until two (or three) terminals are found which illicit a twitch. And which is + and which is - doesn't matter either!

-Please let me know how it goes, I'd love to see a classroom full of permutations!